* {
    margin: 0;
    padding: 0;
    font-family: "Source Code Pro";
    box-sizing: border-box;
    outline: none;
    list-style: none;
}

body {
    width: 100%;
    height: 100vh;
    overflow: hidden;
}

section {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    background: linear-gradient(rgba(183 183 255 / 50%), rgba(255, 153, 153, 0.3));
    overflow: hidden;
}

section::before {
    content: '';
    position: absolute;
    z-index: 2;
    width: 450px;
    height: 450px;
    top: 50%;
    left: 50%;
    transform: translate(-100%, -100%);
    background-color: #ffe538;
    background-image: linear-gradient(145deg, #FFE538 0%, #FF7D25 80%);
    border-radius: 50%;
    box-shadow: 0 0 0 0 rgba(239 187 135 / 100%)
    animation: pulse 1.5s infinite;
}

section::after {
    content: '';
    position: absolute;
    z-index: 2;
    width: 300px;
    height: 300px;
    top: 50%;
    left: 50%;
    transform: translate(10%, 10%);
    background-color: #FA8BFF;
    background-image: linear-gradient(45deg, #FA8BFF 0%, #2BD2FF 50%, #2BFF88 80%);
    border-radius: 50%;
    box-shadow: 0 0 0 0 rgba(184 237 255 / 100%);
    animation: pulse 1.6s infinite;
}

@keyframes pulse {
    50% {
        box-shadow: 0 0 0 50px rgba(255, 255, 255, 0);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(255, 255, 255, 0);
    }
}

form {
    position: relative;
    z-index: 3;

    /* 水平居中 */
    width: 320px;
    margin: 0 auto;

    background-color: rgba(255, 255, 255, .1);
    padding: 45px 30px;
    border-radius: 8px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, .1);
    border: 1px solid rgba(255, 255, 255, .2);
    border-right: 1px solid rgba(255, 255, 255, .1);
    border-bottom: 1px solid rgba(255, 255, 255, .1);
    backdrop-filter: blur(10px);
}

form h2 {
    color: #fff;
    text-align: center;
    margin: 0 0 30px 0;
}

input {
    font-size: 1.25em;
    width: 100%;
    height: 50px;
    border-radius: 8px;
    color: #fff;
    background-color: transparent;
    border: 1px solid rgba(255, 255, 255, 1.0);
    margin-bottom: 15px;
    padding-left: 15px;
}

input::placeholder {
    color: rgba(255, 255, 255, .8);
}

input:focus {
    color: #A48CFF;
}

input:focus::placeholder {
    position: absolute;
    top: 0;
    right: 15px;
    line-height: 50px;
}

input:valid {
    color: #A48CFF;
}

button {
    font-size: 1.25em;
    width: 100%;
    height: 50px;
    border: 0;
    border-radius: 8px;
    background-image: linear-gradient(to right, #FF7D25 0%, #2BD2FF 100%);
    background-size: 200% auto;
    color: #fff;
    cursor: pointer;
    box-shadow: 0 20px 40px rgba(255, 255, 255, 0.5);
    transition: ease .5s;
}

button:hover {
    background-position: right center;
    color: #fff;
    text-decoration: none;
}
